A PGA socket is disclosed in U.S. Pat. No. 5,299,950 (FIGS. 1 and 6A). This type of IC socket comprises socket contacts, having pairs of resilient contact portions and a connecting portion, which is formed in a substantially C-shape, for connecting the resilient contact portions. This IC socket further comprises cavities, which are arranged in a two dimensional matrix to house the socket contacts. Lead pins of an IC package are inserted with zero or low insertion force into proximal end portions of the pairs of resilient contact portions, where the gaps therebetween are comparatively wide. Next, the lead pins are moved toward the distal ends of the resilient contact portion pairs, where the gaps therebetween are narrow. Thereby, the lead pins are electrically connected with the socket contacts, and held between the distal ends of the resilient contact portions. In this known PGA type IC socket, housing walls of the cavities, in the proximity of the distal ends of the resilient contact portions, prevent disengagement of the lead pins from the socket contacts, and also position the IC package. Accordingly, the housing walls that form the cavities are indispensable.
In the known IC socket described above, there is a possibility that the lead pins will interfere with the cavity walls during insertion and horizontal movement of the lead pins. Therefore it is necessary to occupy a certain sized space for the cavities. Accordingly it is difficult to achieve high density socket contacts at narrow pitches due to these dimensional constraints.